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don't always use pha/pla in pointer expression code

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This commit is contained in:
Irmen de Jong 2021-02-27 16:21:46 +01:00
parent 2b435fe6a5
commit e6079dfd71
2 changed files with 42 additions and 28 deletions
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61
compiler/src/prog8/compiler/target/c64/codegen/AsmGen.kt
View File

@ -1407,39 +1407,44 @@ $label nop""")
internal fun tryOptimizedPointerAccessWithA(expr: BinaryExpression, write: Boolean): Boolean {
// optimize pointer,indexregister if possible
fun evalBytevalueWillClobberA(expr: Expression): Boolean {
val dt = expr.inferType(program)
if(!dt.istype(DataType.UBYTE) && !dt.istype(DataType.BYTE))
return true
return when(expr) {
is IdentifierReference -> false
is NumericLiteralValue -> false
is DirectMemoryRead -> expr.addressExpression !is IdentifierReference && expr.addressExpression !is NumericLiteralValue
is TypecastExpression -> evalBytevalueWillClobberA(expr.expression)
else -> true
}
}
if(expr.operator=="+") {
val ptrAndIndex = pointerViaIndexRegisterPossible(expr)
if(ptrAndIndex!=null) {
val pointervar = ptrAndIndex.first as? IdentifierReference
if(write) {
when(ptrAndIndex.second) {
is NumericLiteralValue, is IdentifierReference -> {
if(pointervar!=null && isZpVar(pointervar)) {
out(" pha")
assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
out(" pla | sta (${asmSymbolName(pointervar)}),y")
} else {
// copy the pointer var to zp first
out(" pha")
assignExpressionToVariable(ptrAndIndex.first, asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, null)
assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
out(" pla | sta (P8ZP_SCRATCH_W2),y")
}
}
else -> {
// same as above but we need to save the A register
if(pointervar!=null && isZpVar(pointervar)) {
out(" pha")
assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
out(" pla | sta (${asmSymbolName(pointervar)}),y")
} else {
// copy the pointer var to zp first
assignExpressionToVariable(ptrAndIndex.first, asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, null)
out(" pha")
assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
out(" pla | sta (P8ZP_SCRATCH_W2),y")
}
}
if(pointervar!=null && isZpVar(pointervar)) {
val saveA = evalBytevalueWillClobberA(ptrAndIndex.second)
if(saveA)
out(" pha")
assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
if(saveA)
out(" pla")
out(" sta (${asmSymbolName(pointervar)}),y")
} else {
// copy the pointer var to zp first
val saveA = evalBytevalueWillClobberA(ptrAndIndex.first) || evalBytevalueWillClobberA(ptrAndIndex.second)
if(saveA)
out(" pha")
assignExpressionToVariable(ptrAndIndex.first, asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, null)
assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
if(saveA)
out(" pla")
out(" sta (P8ZP_SCRATCH_W2),y")
}
} else {
if(pointervar!=null && isZpVar(pointervar)) {

9
examples/test.p8
View File

@ -4,6 +4,15 @@
main {
sub start() {
uword screen = 2000
ubyte i = 1
uword w = 33
str derp ="derp"
ubyte[] array = [1,2,3]
@(screen+i) = 128
@(i+screen) = 129
txt.print("done\n")
}
}